Aileron



y 1946- I w. p. VAN z|-:| M 2,403,776 1 AILERON Filed Nov. 4, 1942 2Sheets-Shet 1 FIGLJREI.

INVENTOR. W|| .EM D. VAN ZELM ATTORNEY 1946. w. D. VAN ZELMA 2,403,770

AILERON Filed Nov. 4, 1942 4 2 Sheets-Sheet 2 .F'IGLJRE 3.

. INVENTOR. WILLEM. D. VAN ZELM tiflsk a M ATT RNEY Patented Jul 9, 1946AILERON,

'Willem D. van Zelm, Ruxton, Md., assignor to The Glenn L. MartinCompany, MiddleRiver,

Md., a corporation of Maryland Application November 4, 1942, Serial No.464,447

This invention relates to an aileron or control surface for a wing orairfoil of greatly increased efficiency as compared to the typeof.

aileron or control surface commonly used.

The aerodynamic efiiciency of the airplane is greatly reduced by the.fact that the provision for lateral control, namely, the ailerons,limits.

the flap area, and as a result increases the takeoff distance ordecreases the take-off load of an airplane. By applicants device, thesame lateral control is provided with less aileron area which results ina greatly increased length of flap with the resultant increase in liftand shortened takeofi distance. e

Frise ailerons have been generally adopted because they furnishaerodynamic balance resulting in low control forces, and also becausethe nose shape which protrudes into the airstream upon an upwarddeflection of the aileron, produces an increase in air drag which helpsin turning the airplane. This last feature is commonly described asfurnishing positive yaw or at least, as reducing the inherent adverseyaw of the ailerons.

In their general acceptance, the defects of the.

Frise'ailerons have been completely overlooked. The nose of the Friseailerons has a large amount .of motion with respect to the wing, and aclearance slot must be provided which results in air leakage from thebottom to the top surface of the wing. This results in increased dragand reduces the rolling moment of the aileron beyond approximately 15 upmotion. This last effect is due to the nose balance, which protrudesinto the airstream below the wing, acting as a spoiler and effectivelystalling the aileron, This is illustrated in Fig. 3 of the drawings, 7,

In short, the Frise aileron obtains its reduction of hinge moments, atthe expense of rolling moments. It is an object of the present inventionto .provide an aileron with provisions for reducing the hinge momentsand at the same time provide increased rolling moments.

Another object, of the invention is to provide balanced aileron whichhas better structural efficiency than the ordinary balancedFrise type.

A further object of the invention is to'provide an aileron which, forall positions, will prevent the flow of air between the lower surfaceand upper surface of the wing, and thus cause all of the airflow on theunder surface of the wing to flow over thelower surface of theaileron. QI

A still further object is the provision of an aileron structure whichdoes not. interfere with the air flow of the under side of the wing-but8 Claims. (Cl. 244'90)' causes a smooth flow of the aileron andpractically eliminates the spoilereffect."

Further and other objects will'become apparent from the description ofthe accompanying drawings which form a part of this disclosure and inWhichlike numerals refer to like parts.

In the drawings:

Figure 1 shows a conventional wing and aileron assembly.

Figure 2 shows, by way of comparison, the improved wing and aileronassembly.

Figure 3 shows the spoiler effect of the Frise type aileron. I

Figure 4 shows the improved aileron in the neutral'position,

Figure 5 shows the improved aileron at a large upward deflection.

,- large upward deflection.

Figure" 6' is a partial section showing the seal at the hinge of theaileron.

Figure 1 shows a wing, having aileron l and flap portion 3. 1 v

Figure 2 shows the" same wing with an aileron 2 designed to give thesame rolling moment as that of aileron 1 By using this improvedaileron,

it will be noted that the flap portion 4 is in 'creased by the amountthe lower rear portion of the aileron.

Figure 4 shows a wing having the improved aileron 2, This aileron issecured to the wing by a hinge comprising brackets 6 and l, bracket 6being secured to the aileron and bracket 1 being secured to the wing. Ahinge pin is represented 4 by the circle 8. It is common practice toemploy three hinges for securing the aileron to the wing. Strip 9 issecured to the wing and extends between the hinges. This strip has abead por- 2 tion Ill, the lower side of which is substantially tangentto the axis of the hinge pins. Strip H is coextensive with strip 9between the hinges and isof a resilient material which contacts thebead. forming a seal to prevent the flow of air between the lowersurface of the wing and the upper surface of the win-g and thus causeall of the air underneath the wing to flow along the under surface ofthe aileron. Due to its construction. the seal is practicallyfrictionless and does not 5.,interfere with the hingeaction of theaileron.

The primary purpose of this seal construction is to minimize friction soas to keep control forces exerted by the pilot to a minimum but permitsthe ready removal of the airfoil for service or repair without the extraoperations required to break and replace a seal.

Slat ill is secured to, but spacedsfrom, the forward lower portion ofaileron 2. This slat has. a negative incidence with respect to the wing.When the aileron is in the neutral position shown in Figure 4, the topand bottom surfaces of the aileron are substantially at the top andbottom planes of the wing and slat I2 is entirely within the bottomplane of the Wing.

For a large upward deflection of the aileron as shown in Figure 5, slatI2 projects into the airstream and due to its airfoil shape, rather thancausing a spoiler effect, it bends the airstream from the lower portionof the wing over the lower surface of the-aileron, thus eliminating theusual stalling effect 'on the aileron; Since the sealbetween the hingeseffectively prevents the flow of air over the top surface ofthe airfoil,all

of the air is caused to flow on the under surfaceof the aileron withsubstantially no turbulence. Slat 42 also has a slight negative lift andadds to the rolling moment of the airfoil as well as acting to balancethe aileron. It will also be notedthat for allpositions-of the aileron,the bottom surface of the aileron proper. never extends beyond the lowerplane of thewing into the airstream but rather remains substantiallytangent to this plane.

A further advantage of the type of hinged construction described isthat. in this upper hinged construction, the brackets 6 and 1.areentirely outside of the ailerons, thus, avoiding-the necessity forcutting the ailerons to attach hinges which reduces the strengthofthestructure, as is usual in the aileron construction. It can be seenfrom Figure 3 that with the internalhinge of the Frisetype aileronit isnecessary to have a cut or slot. in the aileron to'acommodatethemounting bracket 13- From a considerationv of the conventional aileronand applicants improved airfoil, it will be seen. that due totheincreased efiiciency of the improved. structure,- an aileron oftheimproved structure-can be considerably shorter than the conventional.aileron and accomplish the same rolling. moment. Actual testsshow thatfor the same wing, the new aileron. will give the same rolling moment asthe Frisetype, with 35% to 45% less length alongthe span. This willresult in a longer flap, thus increasing the lift efficiency of. theairplane for. takeeoff.

It is to be understood that. certain changes, alterations, modificationsand, substitutions can: be made. without departing from the spirit andscope of the appendedclaims.

I claim as, my invention 1.

1. An aileron mounting forv the trailing edge of an airplane wing,-comprising hinge means movably securing said aileron tosaidwing, saidhinge means comprising brackets secured to the upper leading edge of theaileronwithin the contour of the wing, the axis of said hinge beingclose to-the inside of the upper contour of said wing and the lowerleading portion of said aileron having a contour so that for maximumupwardde'flectionsof the aileron, the contour'of said aileron remainsapproximately in the plane of the lower surface of said'wing, stripssecured to the top surface of said wing and said aileron extending thelength of the aileron which engage each other and cover the spacetherebetween to prevent the flow of air therethrough, a, slat secured infixed-spaced relation to the lower leading edge of said aileron having anegative lift with respect to said wing when said slat is in itsoperative position, said slat moving with said aileronlinto aninoperatveposition between the wing and the aileron when said aileron is in theneutral or down position and into an operative position extending intothe airstream below said wing upon an upward movement of the aileronwhereby all of the air flow on the under side of the wing is bentwithout turbulence around the lower surface of said aileron to effect anincrease in rolling moment of said wing,-

2. An aileron mounting for an aircraft wing, comprising a plurality of.hinges for movably securing said aileron to said wing, the axis of saidhinges lying approximately in the plane of the upper surface of saidwing, a slat secured to the leading edge of said aileron, said slatbeing spaced from said aileron and having a negative lift with respectto said wing. when in the operative position, said slat being retractedwithin the plane of the lower surface of said wing when said aileron isin the neutral or down position, and extending into the airstream belowsaid'wing upon an upward movement of the aileron whereby the airflow isbent around said aileron to minimize'turbulence, and sealing meansbetween said hinges to-prevent airflow between said aileron and saidwing, to cause all of the airstream on the under side of said wing toflow on the under side of said aileron.

3. An aileron assembly for arr-airplane wing, comprising a controlairfoil movably secured to thetrailing edge of said wing, a negativelift slat secured to the forward lower portion of said con- "face ofsaid wing when said control airfoil is in the neutral or down position,and hinge means within the contour of the airfoil close to the plane ofthe upper surface of said airfoil for movably securing said airfoil tosaid wing, and sealing means extending throughout the length of saidairfoil to prevent the flow of air from the under side of the wingthrough the space between said airfoil and said wing.

4. An aileron assembly for the trailing edge of an airplane wing;comprising hinge means for movably securing said aileron to said wing,the axis of said hinge lying approximately in the plane of the uppersurface of said wing, strips secured to the top surface of said wing andsaid aileron extending the length of the aileron which interengage andcover the space therebetween to prevent the flow of air therethrough, aslat secured in fixed spaced relation to the lower leading edge of saidaileron having a negative lift with respect to said wing when in theoperative position, said slat moving with said aileron to an inoperativeposition between the wing and the aileron when said aileron is in theneutral or down position, and into a position extending into theairstream below said winglupon an upward movement of said aileron,whereby all of. the airflows with substantially no turbulence along the.underside of the aileron to effect an increasedrolling moment of saidwing. I

5. An aileron'mounting for an aircraft wing,

comprising a control airfoil movably secured to the rear portionthereof, hinge means for securing forward lower portion of said controlairfoil extending into the airstream-when said control airfoil is in theup position, said slat being movable with said airfoil within the planeof the lower surface of said wing when said control airfoil i in theneutral or down position.

6. An aileron mounting for an aircraft wing, means for hingedly securingsaid aileron to the trailing edge of said wing, comprising a pluralityof complementary brackets mounted on said aileron and said wing to formhinges, the brackets on the aileron being mounted on the exteriorthereof, hinge pins securing said brackets together, the axis of saidhinge pins being adjacent the underside of the upper surface of saidvwing, so that the leading edge of the aileron is maintainedapproximately within thev profile of the wing for all positions of theaileron, sealing means adjacent said hinges closing the space betweensaid wing and said aileron, a slat mounted on the leading edge of saidaileron, said slat being spaced from the lower side of the leading edgeof said aileron and having a negative lift with respect to said wingwhen the slat is in its operative position, said slat being movable withsaid aileron to a position within the contour of the lowersurface ofsaid wing when the aileron is in the neutral or down position andextending into the airstream below said wing upon an upward movement ofsaid aileron whereby all of the air flow along the lower surface of thewing is bent around the lower surface of said aileron with sub-'stantially no turbulence. r

'7. Control airfoil mounting on an airplane wing comprising a pluralityof hinges for movably securing said airfoil to said wing, the axis ofsaid hinges lying approximately in the plane of the upper surface ofsaid wing and strips extending between said hinges, one secured to saidairfoil and, one secured to said wing meeting with line contactsubstantially at the axis of said hinges for closing the passage betweensaid airfoil and said wing against airflow therebetween.

8. Control airfoil mounting on an airplane wing comprising a pluralityof hinges for movably secontact substantially at the axis of said hingesfor closing the passage between said airfoil and said wing againstairflow therebetween, a negative lift slat secured to the forward lowerportion of said airfoil, extending into the airstream onthe under sideof said wing when th control surface is in the up position, said slatbeing movable with said airfoil within the plane of the lower surface ofsaid wing when said control is in the neutral or down position.

WILLEM D. vim ZELM.

